Classifications

• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/025—Re-forming glass sheets by bending by gravity
  • C03B23/0252—Re-forming glass sheets by bending by gravity by gravity only, e.g. sagging
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/03—Re-forming glass sheets by bending by press-bending between shaping moulds
  • C03B23/0302—Re-forming glass sheets by bending by press-bending between shaping moulds between opposing full-face shaping moulds
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B23/00—Re-forming shaped glass
  • C03B23/02—Re-forming glass sheets
  • C03B23/023—Re-forming glass sheets by bending
  • C03B23/035—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending
  • C03B23/0352—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet
  • C03B23/0357—Re-forming glass sheets by bending using a gas cushion or by changing gas pressure, e.g. by applying vacuum or blowing for supporting the glass while bending by suction or blowing out for providing the deformation force to bend the glass sheet by suction without blowing, e.g. with vacuum or by venturi effect
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B25/00—Annealing glass products
  • C03B25/02—Annealing glass products in a discontinuous way
  • C03B25/025—Glass sheets
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
  • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
  • C03B35/145—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by top-side transfer or supporting devices, e.g. lifting or conveying using suction
• • C—CHEMISTRY; METALLURGY
  • C03—GLASS; MINERAL OR SLAG WOOL
  • C03B—MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES
  • C03B35/00—Transporting of glass products during their manufacture, e.g. hot glass lenses, prisms
  • C03B35/14—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands
  • C03B35/20—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by gripping tongs or supporting frames
  • C03B35/202—Transporting hot glass sheets or ribbons, e.g. by heat-resistant conveyor belts or bands by gripping tongs or supporting frames by supporting frames

Definitions

• the invention relates to a method for producing curved glazing, in particular laminated glazing, and proposes an improvement of the step of cooling the glass after its bending in order to obtain reduced extension stresses.
• the invention relates to bending processes involving a bending step on a gravity bending support said gravity support.
• the invention relates in particular to the production of laminated glazing type windshield or pavilion for road vehicle (automobile, truck, bus), but also any glazing for aeronautics or building.
• the tooling supporting the so-called "gravity support” glass In the gravitational bending processes, the tooling supporting the so-called "gravity support" glass, of a shape adapted to the final geometry of the glass, is in contact with the periphery of the lower face of the glass during all the shaping phases. that is to say the roughing of the bending, bending and cooling.
• a gravity support is usually in the form of a frame. It is preferably coated with a refractory fibrous material well known to those skilled in the art to come into contact with the glass.
• the width of its contact track with the glass is generally in the range of 3 to 20 mm, refractory fiber material included.
• the glass When the glass leaves the bending stage to start the cooling phase, it is, according to the prior art, usually in contact with its periphery with the last gravity support, in particular between 5 and 10 mm from the edge of the glass.
• the glass freezes and cools, a physical phenomenon of genesis of permanent stresses is created which corresponds to the conversion of the temperature distribution within the glass into a stress field. This phenomenon is initiated during the freezing of the glass and ends at the end of cooling when a homogeneous distribution of temperature is reached.
• the parts where the glass has frozen in the first place correspond to the parts where the compressive stresses are concentrated whereas the parts where the glass has frozen with delay concentrate the stress zones in extension.
• the edge stresses described in the present invention are membrane stresses which can be defined at any point in the material and for a given direction, such as the average of the field constrained at this point and in this direction, the average being carried out in all directions. thickness of the sample. At the edge of the sample, only the membrane stress component parallel to the edge is appropriate; the perpendicular component has a zero value. Also any measurement method allowing measurement of average stresses along an edge and across the thickness of the sample is relevant. The methods for measuring edge stresses use photoelasticity techniques. The two methods described in ASTM standards listed below allow the measurement of edge stress values:
• the compressive stress values are determined between 0.1 and 2 mm of an edge and preferably between 0.1 and 1 mm of an edge.
• an area of extended edge stresses is generally identified which is included in a peripheral zone located between 3 and 100 mm from the edge of the glass.
• the extension stresses relate to the membrane stresses of the glass sheet in the outer position in the glazing (mounted on the vehicle) which can be measured on the outer glass sheet alone before laminated assembly. either on the outer glass sheet after laminated assembly using the commercial Sharples model S-69 sold by Sharples Stress Engineers, Preston, UK.
• This sheet in the outer position on the vehicle corresponds to the sheet in the lower position during bending by the method according to the invention, and in the case of a stack of glass sheet.
• the invention makes it possible to avoid the disturbance of the temperature distribution induced by the contact of the periphery of the glass with a gravitational support during its cooling. Also, the compression levels of the edges mentioned above are more easily achievable with greater safety margins, and the levels of extension stress are reduced.
• EP2532625 teaches a device for supporting glass after cooling its surface below its strain point.
• the central zone of the glass is cooled under the strain point before the border.
• This technique is applied to glass annealing.
• the cooling of the interior of the glass is necessary to lift the glass from its support. This causes compression of this central area, which must necessarily be offset by an extended area at the periphery thereof.
• the cooling of the central zone may therefore result in the creation of larger peripheral expansion stresses that can weaken the glass.
• the annealing step is insufficiently controlled and the glass remains too long at too high temperature during this phase, the level of surface compression may be insufficient.
• the cooling rate depends on many parameters related to the furnace; mention can be made of the cycle time, the weight of the glazings and on-board tools, the pressure installed in the furnace; this is difficult to control and requires numerous parameterization tests and on-board temperature measurements;
• the glass is in the form of a single sheet or more generally in the form of a stack of several sheets, more generally still, a stack of two sheets.
• it is simply called "glass" to designate a sheet or a stack of sheets.
• the glass comprises two main external faces, called here first main face and second main face, the gravity bending being performed on a gravity support by glass support on its first main face, which is turned down.
• first main face and second main face the gravity bending being performed on a gravity support by glass support on its first main face, which is turned down.
• the sheets remain stacked during the whole process of bending and cooling, to ensure identical forming of all the sheets to be assembled.
• the combination of these sheets of glass in the final laminated glazing is thus achieved under better conditions, leading to a laminated glazing of better quality.
• the invention relates to the method of the independent process claim.
• the invention also relates to the device independent claim device.
• the method according to the invention can be implemented using the device according to the invention.
• the invention more particularly relates to a curved glass manufacturing method comprising the bending and cooling of a glass sheet or a stack of glass sheets, said glass, comprising a first main face and a second main face, said method comprising gravity bending of the glass on a gravity support during which the glass rests on the gravity support by contact with the peripheral zone of its first main face, said peripheral zone consisting of 50 mm from the edge of the first main face, then the separation of the glass gravity support while the glass is more than 560 ° C, then the cooling of the glass during which its first main face is free of all contact in its peripheral zone, between a so-called higher homogeneous temperature temperature, of at least 560 ° C and a so-called lower homogeneous temperature, of at most 500 ° C, said critical temperature range.
• the peripheral zone of the first main face of the glass is non-contacting in the critical temperature range, which means that this peripheral zone is free of any contact with a solid, that is to say to say is exclusively in contact with the gaseous atmosphere.
• the contact with the gravity support is entirely in the peripheral zone, without contact with the glass beyond the peripheral zone.
• the separation of the glass from the gravity support takes place while this one is at more than 560 ° C, it being understood that the entire glass (peripheral zone and central zone) is above this temperature at this time.
• the zone of the first main face further than 50 mm from the edge of the glass, called the central zone is at a temperature greater than that of the peripheral zone.
• the central region of the first main face of the glass is a temperature at least equal to, and generally greater than that of the peripheral zone at the moment when the peripheral zone reaches the higher homogeneous temperature and preferably also at the moment when the peripheral zone reaches the lower homogeneous temperature, and more generally between the moment of separating the gravity support until at least the moment when the peripheral zone reaches the higher homogeneous temperature and even the lower homogeneous temperature.
• the temperature range between the upper homogeneous temperature and the lower homogeneous temperature is called the critical temperature range and the time to pass from the homogeneous higher temperature to the lower homogeneous temperature is called the critical cooling time.
• the higher homogeneous temperature is at least 575 ° C.
• the lower homogeneous temperature is at most 490 ° C.
• the first main face of the glass is non-contact in its 60 mm from the edge and preferably without contact in its 70 mm from the edge.
• the first main face of the glass is non-contacting beyond 200 mm from the edge and preferably without contact beyond 170 mm from the edge and preferably without contact beyond 150 mm from the edge. It is therefore possible to define a "band of contact "of the first main face of the glass in which the glass is preferably supported as long as it is in the critical temperature range:
• outer limit of the strip at least 50 mm and preferably at least 60 mm and preferably at least 70 mm from the edge of the glass
• - inner limit of the strip not more than 200 mm and preferably not more than
• homogeneous temperature is meant that the temperature of the glass does not vary more than 5 ° C and preferably not more than 1 ° C, and preferably not more than 0.6 ° C on these 50 mm of peripheral area.
• the homogeneous temperature of the glass is checked by measurements with the aid of a thermal camera on the first main face of the glass. This homogeneity is achieved for each of the sections perpendicular to the edge of the glass, but one section may have a temperature different from another section.
• the peripheral zone of the first main face is homogeneous in temperature on any line at the intersection of a section perpendicular to the edge of the glass in the critical temperature range (between the upper homogeneous temperature and the lower homogeneous temperature).
• the glass used in the context of the present invention is a soda-lime glass. It is conventionally formed by the float process and commonly used for automotive applications. According to the invention, the control of the stresses generated in the glass is improved by separating it from its last gravitational support, then by homogenizing the temperature of its peripheral zone and cooling the glass to the end of the critical range of temperature. maintaining a homogeneity of temperature.
• This first main face, also called “face 1" by the skilled person is usually convex (the face 4 is the inside of the vehicle if the laminated glazing comprises two sheets of glass).
• the first main face of the glass is separated from the last gravity support at a temperature greater than the upper homogeneous temperature so as to homogenize the temperature of the peripheral zone of this face.
• the glass can be placed on this same face on a specific support in at least a part of the critical temperature range to continue cooling the glass while maintaining the temperature homogeneity of the peripheral zone. Once the temperature of this first main face is homogeneous in its peripheral zone the glass can be cooled more rapidly, even in the critical temperature range.
• the edge compression stresses of the final glass in its sheet comprising the first main face are greater than 8 MPa, or even greater than 10 MPa and can even be up to 20 MPa, and are more homogeneous on along the periphery of the glass.
• the extension levels are significantly reduced, less than 5 MPa and even less than 4 MPa, or even less than 3 MPa.
• the passage from the compression zone to the extended zone is generally at a distance from the edge of between 1 and 5 mm.
• the maximum stress extension is generally at a distance from the edge of between 5 and 40 mm and more generally between 15 and 40 mm.
• the mechanical strength of the glazings obtained can be evaluated by impacting the face 1 of the glazing with Vickers tips. Such a test makes it possible to evaluate the resistance to graveling glazing when installed on the vehicle. The higher the impact energy of the indenter, without the glass cracking, the greater its robustness.
• the glazings obtained by the process according to the invention are more robust than when their manufacture includes their cooling on their gravitational support. This improved robustness is imputed a reduced level of edge extension.
• edge expansion constraints which, in the first order, determine the fragility of the glazings is a membrane stress, equivalent in every point M of the surface of a glass sheet to the average constraints in the thickness of it at this point. This average is thus carried out along the segment "S" which is perpendicular to the glass sheet at the point M and which passes right through it. Also, there may be different stress profiles along the segment S which correspond to the same value of stress in extension. Among the various possible stress profiles, the profiles whose first main face of the glass is in compression are the most interesting for the mechanical strength.
• the skin in compression of the first main face then acts as a protective layer which blocks the propagation of surface defects and prevents them from becoming a crack both in the thickness and in directions parallel to the surface of the glass sheet.
• the stress profiles that must be avoided are those in which the first main face of the glass is in extension.
• the cooling of the glass on its gravity support promotes both a mean cooling delay (in the thickness of the outer sheet of the glass) along an inner area to the glass and located near the edge but also, in this same peripheral zone, a cooling delay of the first main face of the glass which, consequently, has itself tend to be extended.
• the improved robustness of the glass obtained according to the invention is therefore also attributed to a higher level of surface compression overall.
• this peripheral zone is preferably free of any contact with any tool (that is to say in contact exclusively with the gaseous atmosphere). sufficient for the homogenization to be obtained before reaching the higher homogeneous temperature.
• This homogenization time in temperature is generally at least 5 seconds and preferably at least 6 seconds and even at least 7 seconds. Preferably it is the whole of the first main face which is without any contact during this period of temperature homogenization.
• This homogenization is well obtained by maintaining the glass by suction on its second main face and without any contact with its first main face, thanks to an upper shape provided with a skirt and a suction means sucking the air between it and the skirt, hereinafter referred to simply as the upper form, the suction of the skirt providing the holding force of the glass against the shape.
• an upper form is for example described in Figure 3 of WO201 1/144865, the skirt being the element 39.
• the air sucked by the skirt and circulating in the vicinity of the edge of the glass promotes the homogenization of the temperature of the peripheral zone of the first main face of the glass.
• the upper form preferably the form of a frame, this frame being preferably covered with a refractory fibrous material to reduce the risk of marking the surface of the second main face of the glass.
• This frame may have a width in the range of 3 to 20 mm, including the fibrous material.
• This upper form comes into contact with the glass without exceeding its edge so as not to disturb the flow of suction air.
• This upper shape can come into contact with the glass so that its outer edge reaches a distance from the edge of the glass in the range of 3 to 20 mm.
• the glass is not excluded to rest the glass above the upper homogeneous temperature on a specific support maintaining the temperature homogeneity of the peripheral zone of the first main face of the glass. If a specific support is used, it is better to rest the glass on it below the higher homogeneous temperature.
• the glass can be carried by a specific support (or several successively) at least up to the lower homogeneous temperature (end of the critical cooling time) and generally also at lower temperature than the lower homogeneous temperature. Where appropriate, the glass may be successively supported by a plurality of specific supports between a temperature within the critical temperature range and a temperature below the critical temperature range.
• the bending of the glass may comprise an additional bending against a solid form of bending.
• This complementary bending follows the bending on the gravity support.
• This complementary bending can in particular be performed on a lower bending mold, particularly by suction, said lower suction mold.
• This lower suction mold is a solid form provided with openings through which suction on the first main face of the glass is achieved. This solid form is at least as big as the leaf and therefore goes to its edge. It does not significantly alter the homogeneity or not of the temperature of the peripheral zone of the first main face of the glass.
• Such a lower suction mold is for example of the type shown in Figure 2 of WO2006072721.
• a complementary bending For the case where a complementary bending is performed, it takes place at a temperature above 570C and even above 580 ° C.
• the temperature of the complementary bending is generally lower than that of gravity bending. After this complementary bending, it is appropriate to separate the glass from the lower suction mold and to leave the peripheral zone of the first main face of the glass without contact the time required for the homogenization of the periphery of the lower face of the glass before it does not reach the higher homogeneous temperature.
• the first main face of the glass is in contact with the gravitational support, then possibly with a lower suction mold, then with at least one specific support.
• the passage of the gravity support to the lower suction mold or directly to the specific support can advantageously be achieved by the use of a suction upper form.
• the passage of the lower suction mold to the specific support can also advantageously be achieved by the use of a suction upper form.
• a higher shape supports the glass by its second upper face and the drop on a support placed under it and can support the glass from below, whether it is a lower mold aspirant or specific support.
• the suction means of a higher form is engaged when it must take the glass load and is stopped so that it can drop the glass.
• the supports (gravity support, suction bottom mold, specific support) to be unloaded or loaded with the glass by an upper form are generally movable laterally and can pass in the upper form to make possible the transfer of the glass with the upper form. To make this transfer possible, these supports and / or the upper form are animated with a relative vertical movement allowing them to move closer or further away.
• the upper shape can support or drop the glass on one of these supports. This transfer being realized, the upper shape and the support move away vertically and the support (loaded or not the glass depending on the type of transfer) moves laterally. Another carrier loaded or not the glass according to the transfer to be made can then be placed in the upper form.
• the glass is slightly pressed at its periphery between the upper form and the lower mold sucking the time that the suction of the lower suction mold is triggered in order to seal the periphery of the first main face of the glass with the lower suction mold and the periphery of the possible different sheets of glass together in a stack.
• the suction by the lower suction mold then acts immediately on the underside of the glass (without leakage from the edges), and in case of stacking, the vacuum is communicated to all its sheets.
• the lower suction mold and the upper form depositing the glass on it have complementary shapes.
• the device according to the invention may comprise several juxtaposed chambers maintained at different and decreasing temperatures in the path of the glass.
• the first chamber on the way to the glass is called a separation chamber and includes a superior form of charged separation to separate the glass from its last gravity support and to drop it on a specific support or on a lower suction mold.
• the last chamber on the way to the glass is called the cooling chamber and usually does not include a superior shape.
• a specific support carrying the glass said specific cooling medium can enter and the glass can be discharged through a support said unloading support, the latter passing under the glass and back to take charge and out of the room cooling.
• the device may further comprise a transfer chamber located between the separation chamber and the cooling chamber, in particular for the case where the upper form of separation drops the glass on a preliminary support preceding the specific cooling support.
• This preliminary support may be a lower suction mold or a specific support different from the specific cooling medium, and called preliminary specific support.
• the transfer chamber is equipped with a higher shape whose role is to discharge the glass of the preliminary support from the separation chamber to drop it on the specific cooling medium.
• the device according to the invention generally comprises two or three chambers each maintained at substantially constant temperature but whose room temperature decreases on the path of the glass.
• the specific mobile cooling support laterally shuttles between the two chambers. It receives the glass in the separation chamber, then goes into the cooling chamber in which it is discharged from the glass, then it returns empty in the separation chamber to receive the next glass, and so on.
• the laterally movable preliminary support moves between the separation chamber in which it receives the glass and the transfer chamber in which it is discharged from the glass, and then returns to empty in the separation chamber for receive the next glass, and so on.
• the specific cooling support laterally movable, commutes between the transfer chamber in which it receives the glass and the cooling chamber in which it is discharged from the glass, and then returns to empty in the transfer chamber. to receive the next glass, and so on.
• the presence of an additional chamber allows more gradual staging of the temperature drop.
• the temperature of gravity media may be higher at the entrance of the bending furnace. Indeed, these media being discharged at more than 560 ° C, they can return relatively hot, especially at temperatures between 200 and 500 ° C at the entrance of the oven without undergoing strong cooling. Maintaining the gravity media at high temperatures significantly reduces the amount of energy required to heat them and moreover, they also serve to heat the glass as soon as it is loaded. The path to be covered by gravity media is also shortened. All these elements are in the direction of reducing costs.
• the gravitational supports each loaded with glass can circulate by train in a tunnel furnace for the purpose of bending the glass by gravity generally between 590 and 750 ° C., depending on the composition of the glass.
• the oven temperature decreases towards the end producing a slow cooling, between 0.4 and 0.8 ° C / second, until the glass has a temperature generally close to 585 ° C.
• the train passes in the upper separation form, the latter taking charge of the glass of each of the gravitational supports one after the other.
• the separation of the glass from its gravity support occurs at more than 560 ° C. and preferably more than 575 ° C. ° C or even more than 590 ° C.
• the glass collapses under the effect of its weight by passing through the tunnel oven at its plastic deformation temperature before arriving in position in the upper separation form.
• Each support each carrying curved glass forms a stop in the upper form of separation.
• the shape is sufficiently close to the glass to be able to take charge after triggering its suction.
• the first upper form then rises so that a support (of the specific support type or lower suction mold) movable laterally can be placed in position beneath it. She then approaches this support and drops on him the glass by stopping his aspiration.
• the glass passes all the critical range of temperature either by being supported by at least one specific support, or by being maintained by its second main face by at least one upper form provided with a suction means, so that the peripheral area of the first main face of the glass is never in contact with a solid.
• the devices used comprise a separation and transfer means capable of separating the glass from the gravity support and depositing it on a specific cooling medium.
• the separation and transfer means comprises a superior form of separation provided with a suction means, in particular of the skirt type, making it possible to hold the glass against it by its second main face, said upper form of separation being able to take charge of the glass by unloading the gravity support.
• the aspiration works so that the upper form of separation can take over the glass by unloading the gravity support, and then move away from the gravity support by carrying the glass.
• the upper shape holding the glass against it is then positioned above another support, then the suction is stopped so that the upper form can drop the glass on the other support.
• this other support may directly be the specific cooling support, or may be a preliminary support preceding the specific cooling support.
• This preliminary support may be a lower suction mold or a specific support different from the specific cooling medium, and called preliminary specific support.
• the upper form of separation holds the glass by its second main face, which allows in particular the first main face of the glass to be then free from contact with any solid, which is favorable to the temperature homogenization of this first main face of the glass in its peripheral zone.
• the separating and transferring means comprises a separation chamber comprising a superior form of separation provided with a suction means of the skirt type, for retaining the glass against it by its second main face.
• the gravity support is movable laterally and able to position itself in the upper separation form, the gravity support and the upper separation form are able to move closer or further away (by the movement of one or the other or of the two) so that the upper form of separation can take charge of the glass by unloading the gravity support and then move away from it in the separation chamber with the glass, the specific cooling support is laterally movable and able to position itself in the upper separation form or to move away from it, the specific cooling support and the upper separation form are able to move closer or further away (by the movement of one or the other). other or both) so that the upper form of separation can drop the glass on the specific cooling medium.
• the gravity support carrying the glass is positioned in the upper separation form, then the glass is separated from the gravity support by the upper separation form and maintained by the upper separation form in the separation chamber at a temperature lower than the temperature.
• the specific cooling support being movable laterally and able to enter or leave the separation chamber, is positioned under the glass and the upper form of separation leaves the glass on it, then the specific cooling support carrying the glass leaves the separation chamber for the further cooling of the glass
• the glass on its gravity support passes under the separation chamber.
• the upper form of separation and the gravity support are then approached by a relative vertical movement and the upper form of separation supports the glass by separating it from the gravity support and raises it sufficiently high in the separation chamber so that the specific support of cooling, then empty, can pass under the glass.
• the temperature of the separation chamber is lower than that of the glass when it is taken over by the upper form of separation.
• the temperature of the separation chamber may be between 540 and 585 ° C.
• the suction serving to hold the glass against the upper form of separation by the second main face of the glass contributes to the homogenization of the temperature of the peripheral zone of the first main face of the glass.
• the glass is thus maintained at least 5, and even at least 6 or even at least 7 seconds.
• the upper form of separation and the specific cooling support are then brought closer by a relative vertical movement and the upper form of separation drops the glass on the specific cooling support, then the upper form of separation and the specific cooling support separate from each other. new.
• the specific cooling support then carries the glass by a lateral movement in a cooling chamber whose temperature is brought to a temperature lower than the temperature of the separation chamber, and in particular may be between 400 and 565 ° C.
• the upper form of separation can then support the next glass.
• An unloading support then enters the cooling chamber, passes under the glass then rises taking it into charge and the fate of this chamber for further cooling.
• the passage of the first main face of the glass (in the lower face position) under the higher homogeneous temperature can be carried out on the specific cooling support but is preferably carried out while the glass is held against the upper form of separation, the glass being then placed on the specific cooling medium in the critical temperature range.
• the glass can be cooled relatively quickly, at an average speed of between 0.8 to 2.5 ° C / second.
• the glass may exit the cooling chamber while being carried by the unloading support while its first main face is still in the critical temperature range, if the unloading support is a specific support type support.
• the unloading support supports the glass while the latter is at a temperature between 520 and 540 ° C.
• a separation chamber comprising a superior form of separation provided with a suction means, in particular of the skirt type, making it possible to hold the glass against it by its second main face,
• a transfer chamber comprising a top transfer shape provided with a suction means, in particular of the skirt type, making it possible to hold the glass against it by its second main face,
• a specific preliminary support adapted to support the glass without contact with the peripheral zone of its first main face.
• the gravity support is movable laterally and able to position itself in the upper separation form, the gravity support and the upper separation form are able to move closer or further away (by the movement of one or the other or of the two) so that the upper form of separation can support the glass by unloading the gravity support and then move away,
• the preliminary specific support is laterally movable and able to enter the separation chamber, to to position itself in the upper separation form, the preliminary specific support and the upper separation form are able to move closer or further away so that the upper separation form can drop the glass onto the preliminary specific support and then can away from it
• the preliminary specific support is able to leave the separation chamber loaded with glass and then able to enter the a transfer chamber (the outlet of the separation chamber and the inlet into the transfer chamber being generally concomitant during the same lateral displacement) and to be positioned in the upper transfer form, the preliminary specific support and the upper form are able to move closer or further away (by the movement of one or the other or both) so that the upper form of transfer can take charge of the glass
• the gravity support carrying the glass is positioned in the upper separation form, then the glass is separated from the gravity support by the upper separation form and held against the upper separation form in a separation chamber at a temperature lower than the temperature.
• glass on the gravity support at the time of separation then the preliminary specific support, movable laterally and able to enter or leave the separation chamber, is positioned under the glass, and the upper form of separation drops the glass on him then the preliminary specific support carrying the glass leaves the separation chamber and enters the transfer chamber equipped with the upper transfer form, the temperature of the transfer chamber being lower than that of the temperature of the separation chamber, then the glass is separated from the preliminary specific support by the higher form of trans fer, then a specific support capable of supporting the glass without contact with the peripheral zone of its first main face, said specific cooling support, is positioned under the glass and the upper form of transfer drops the glass on him, then the specific support coolant carrying the glass leaves the transfer chamber for further cooling of the glass.
• the specific cooling medium carrying the glass can enter a cooling chamber which is brought to a
• the beginning of the process begins as for the previous case (previous case: two chambers and a specific cooling support) until the release of the glass by the upper form of separation since for this, the upper form of separation and the preliminary specific support is bring together relative vertical movement and the upper form of separation drops the glass on the preliminary specific support, then the upper form of separation and the preliminary specific support separate again.
• the preliminary specific support then takes the glass by a lateral movement in the transfer chamber.
• the upper form of separation can then support the next glass.
• the upper transfer shape and the preliminary specific support are brought closer by a relative vertical movement and the upper transfer form supports the glass and rises to let the preliminary specific support empty in the separation chamber. so that he receives the next glass.
• the specific cooling support (unladen at this stage) is positioned in the upper transfer form, then the specific cooling support and the upper transfer form are brought closer together and the upper form
• the transfer device drops the glass onto the specific cooling support and then rises to let go of the specific cooling support carrying the glass in the cooling chamber.
• An unloading support then enters the cooling chamber, passes under the glass then rises taking it into charge and the fate of this chamber for further cooling.
• the passage of the first main face of the glass (in the lower face position) under the higher homogeneous temperature can be achieved while the glass is on the preliminary specific support, in the separation chamber or in the transfer chamber. , or can be achieved while the glass is held against the upper form of separation, the glass being then placed on the preliminary specific support in the critical temperature range.
• the glass can be cooled relatively rapidly, at an average speed of between 0.8 and 2.5 ° C / second.
• the passage of the peripheral zone under the lower homogeneous temperature can be carried out in the cooling chamber.
• the glass can also leave the cooling chamber while being carried by the unloading support while its first main face is still in the critical temperature range, if the unloading support is a support of the specific type. The presence of three rooms allows to stagger a little more gradually the temperature.
• the separation chamber may be in the temperature range 550-590 ° C
• the transfer chamber may be in the temperature range 500-560 ° C
• the cooling chamber may be in the temperature range 350-520 ° C., it being understood that the temperature of the cooling chamber is lower than that of the transfer chamber and that the temperature of the transfer chamber is lower than that of the separation chamber.
• the temperature of the separation chamber is lower than that of the glass when it is taken over by the upper form of separation. From the separation of the glass from the gravity support and at least until the glass outlet of the cooling chamber, the peripheral zone of the first main face of the glass is not in contact with any solid.
• This system is substantially identical to the previous one, except that the preliminary specific support is replaced by a lower suction mold as a preliminary support.
• This mold completes the bending of the glass in the case of relatively complex shapes.
• the temperature range of the chambers is substantially identical to the previous case.
• the passage of the first main face of the glass (in the lower face position) under the higher homogeneous temperature is achieved after the bending on the lower suction mold, especially while the glass is held against the upper form of transfer. The glass is then placed on the specific cooling support in the critical temperature range.
• the separation and transfer means comprises
• a separation chamber comprising a superior form of separation provided with a suction means, in particular of the skirt type, making it possible to hold the glass against it by its second main face,
• a transfer chamber comprising a top transfer shape provided with a suction means, in particular of the skirt type, making it possible to hold the glass against it by its second main face,
• the gravity support is movable laterally and able to position itself in the upper separation form, the gravity support and the upper separation form are able to move closer or further away so that the upper separation shape can take over.
• the lower suction mold is movable laterally and able to enter the separation chamber, to position itself in the upper separation form, the lower suction mold and the upper form separation are able to move closer or further away so that the upper form of separation can drop and press the glass on the lower suction mold and then move away from it, the lower suction mold is able to exit the chamber glass-filled separator then able to enter the transfer chamber (the exit of the separation chamber and the entrance e in the transfer chamber being generally concomitant during the same lateral displacement) and position in the upper transfer form, the lower suction mold and the upper transfer form are able to move closer or further away (by the movement of one or the other or both) so that the upper form of transfer can support the glass by unloading the lower suction mold and then move away from it, the specific cooling support is movable laterally and able to enter or leave the transfer chamber and to position itself in the upper transfer form or to move away from this position, the specific cooling support and the upper transfer
• the gravity support carrying the glass is positioned in the upper separation form, then the glass is separated from the gravity support by the upper separation form and held against it in the separation chamber at a higher temperature. lower than the temperature of the glass on the gravity support at the time of separation, then, a lower vacuum bending mold suitable for bending the glass by suction of its first main face, said lower suction mold, movable laterally and able to enter or out of the separation chamber is positioned under the glass, then the upper form of separation drops the glass on him, then the lower suction mold carrying the glass out of the separation chamber and enters the transfer chamber, the temperature of the transfer chamber being lower than that of the temperature of the separation chamber, the glass being curved on the lower suction mold in the separation chamber and / or the transfer chamber, then the glass is separated from the lower suction mold by the shape superior transfer, then the specific cooling support is positioned under the glass and the upper form of transfer drops the worm re on it, then the specific cooling medium carrying the glass comes out of the transfer chamber for the further cooling of the glass.
• a so-called specific support without contact with the peripheral zone of the first main face of the glass, is used in at least part of the critical temperature range.
• Different types of specific media are possible.
• a specific support comes into contact with the first main face of the glass by a plurality of contact zones touching the glass only in the "contact strip" already defined.
• the support surface of the specific support coming into contact with the glass is therefore discontinuous.
• each contact zone has at its surface a refractory fibrous material well known to those skilled in the art to reduce the risk of marking the hot glass with a tool.
• This fibrous material may be a fabric or felt or knit and especially a "quenching knit" usually used to coat the peripheral rings supporting the glazing during quenching and having the advantage of being very openwork. It contains refractory fibers and has a large open porosity which gives it a property of thermal insulation.
• Such a specific support may comprise 4 to 300 contact zones. The greater the number of contact areas, the smaller the area of contact of each zone. The sum of the areas of all the contact areas may represent 0.2 to 5% of the area of the first major face of the glass sheet in the lower position.
• each contact zone can be in the range from 50 mm 2 to 5500 mm 2 and preferably from 500 mm 2 to 4000 mm 2 .
• the specific support comprises 4 to 20 or even 6 to 20 contact areas of relatively high area each, that is to say with an area each in the range of 500 mm 2 to 4000 mm 2 .
• Such a specific support may have a fixed geometry and perfectly complementary to that of the first main face of the glass with which it must come into contact.
• Such a support may for example have support lines crenellated.
• the support element may comprise a spring damping the reception of the glass during its release by an upper form; the displacement of the contact zone can be guided in the axis of the spring and the support element only has a damping function; however, the spring may not be guided in its axis and can move laterally, in which case the contact zone is automatically oriented in contact with the glass to better marry it;
• the support element may comprise several parts each terminated by a contact zone, said parts being interconnected and being able to orient around a pivot; thus, when the contact area of a portion is lowered as a result of its contact with the glass, the other part of the same support member is pivotally mounted around the pivot until it comes into contact with the glass; the different contact zones of a support element are thus automatically oriented by balancing the weight of the glass around their pivot; a spring can act to push the different parts of the support element upwards and also dampen the reception of the glass.
• a feature of the device is that a higher shape that can act on the glass (support or deposit) to above this specific support has a contact surface for the glass projecting more than 30 mm outward from the contact areas of the specific cooling support.
• the specific support is an inclined peripheral track: the glass is deposited cantilevered by the lower edge of its edge (as the lower edge of its edge) on the track and without contact with the underside of the glass; it is considered that the glass is thus supported from below but without contact with its lower face and outside the peripheral zone.
• This support forms a continuous support surface for coming into contact with the glass.
• a forced convection system can accelerate cooling in the cooling chamber and / or the transfer chamber; such a convection system can be linked to a support or installed in one of these chambers.
• a convection cooling system can be embedded on a specific cooling medium, a preliminary specific support, a specific unloading support.
• a convection cooling system may be installed in the transfer chamber, in the cooling chamber and on the final device for conveying the glass to a cooling zone.
• the routing of the glasses between the cooling chamber and the final discharge zone where the glass is frozen and sufficiently cooled to be handled by operators and stored can be achieved in various ways.
• an unloading support in particular actuated by a robot, can come under the glass, mount to take charge of the glass, and then remove the glass from the cooling chamber. He can then place it on a conveyor leading the glass to a colder unloading area. The robot then returns with the same unloading support to take the next glass in the cooling chamber.
• the method is thus limited to a single unloading support connected to the robot, which avoids the multiple operations of coupling and decoupling of a support with a robot.
• the unloading support is advantageously of the "specific support” type (referred to as “specific discharge support ”) and having a plurality of contact zones with the central zone of the first main face of the glass.
• the specific cooling support and the specific unloading support are both of the type having a plurality of contact zones with the central zone of the first main face of the glass. They can thus come both exclusively in contact in the same surface band of the first main face of the glass, called “contact strip" already defined above.
• the contact areas of these two supports are discontinuous and can therefore intersect at the moment of transfer of the specific cooling support glass to the specific discharge support, in the manner of the branches of two combs. It is in fact preferable to avoid contacting the glass in its central zone beyond 200 mm and preferably above 170 mm and preferably beyond 150 mm from the edge since in the method according to the invention glass is warmer in the central zone than in the periphery and is therefore more sensitive to marking in the central zone.
• this "contact strip" is sufficiently peripheral so that the curve of the glass is well maintained, without collapse of the peripheral zone.
• the unloading support and the specific cooling support both comprise support elements comprising contact zones, which all come into contact with the glass exclusively in a contact strip between an outer limit and an inner limit, the outer limit of the at least 50 mm and preferably at least 60 mm and preferably at least 70 mm from the edge of the glass, the inner limit of the strip being at most 200 mm and preferably at most 170 mm and preferably at most 150 mm from the edge of the glass, the contact areas of the unloading support and the specific cooling support being at least partially inserted in the contact strip at the time of loading of the glass on the unloading support.
• the contact zones of the specific cooling support and the unloading support can all come into contact with the glass exclusively in a contact strip substantially parallel to the edge of the glass, said contact strip being of a width of at most 150 mm, not more than 100 mm, or even not more than 80 mm, the contact zones of the unloading support and the specific cooling support being at least partly inserted in the contact strip at the time of loading of the glass on the support unloading.
• the contact zones of the unloading support and the specific cooling support being at least partly inserted in the contact strip at the time of loading of the glass on the support unloading.
• This property also reflects the fact that the contact areas of the two supports are interposed in a narrow contact strip parallel to the edge of the glass at the time of transfer of the glass.
• the intersection may relate to the contact zone or any part of the support element of the other support.
• the center of a contact zone is, in plan view, the center of gravity of the orthogonal projection of the contact zone on a horizontal plane. This center of gravity is also the geometric center or center of mass of the projection of the zone and can be called “centroid" or "geometry center” in English. This is the point on the surface of the projection of the area corresponding to the centroid of an object of the same shape and thickness infinitely thin and homogeneous in density.
• the cooling rate of the glass only increases globally between the separation of the glass from the gravity support and its outlet from the cooling chamber.
• the average cooling rate of the glass is generally between 0.5 and 1.2 ° C per second.
• the average cooling rate of the glass is generally between 0.8 and 2.5 ° C per second.
• the average cooling rate of the glass is generally between 0.8 and 2.5 ° C. per second.
• the average rate of cooling in a chamber is calculated by the difference in temperature of the glass between the moment of its entry into the chamber and the moment of its exit from the chamber, divided by the time of stay in the room.
• the glass cools more quickly once out of the cooling chamber, with a velocity generally between 2 and 5 ° C per second at least until the glass has the temperature of 400 ° C.
• the cycle time is generally between 10 and 60 seconds, a cycle time being the time elapsed between the passage of two glasses at the same time and place of the process.
• the invention allows the manufacture of a curved glass sheet whose maximum extension stress is less than 4 MPa and even less than 3 MPa, and whose edge compression stress is greater than 8 MPa.
• the passage from the compression zone to the extended zone is generally at a distance from the edge of between 1 and 5 mm.
• the maximum stress extension is generally at a distance from the edge of between 5 and 40 mm, especially between 15 and 40 mm.
• This sheet is the one in the lower position in the stack of sheets having undergone the process according to the invention.
• the face of this sheet, in the lower position in this stack (first main face), is generally convex.
• This sheet may be placed in a laminated glazing unit, the face having been in the lower position in the process according to the invention forming the face 1 of the glazing unit. It is then on the convex side of the glazing.
• the invention relates to the production of laminated glazings combining two sheets of glass whose thickness of one is in the range of 1, 4 to 3.15 mm and whose thickness of the other is included in the range from 0.5 to 3.15 mm.
• the face 1 of the laminated glazing is a face of the thickest sheet.
• Each sheet of glass may be covered before bending one or more layers of enamel or one or more thin layers of the type anti-solar (low-e), conductive or otherwise usually applied to automotive glazing.
• Curved glass made according to the invention relates more particularly to the production of glazing, including laminated, windshield type or road vehicle roof.
• the area of one of their main surface is generally greater than 0.5 m 2 , especially between 0.5 and 4 m 2 .
• a virtual circle with a diameter of at least 100 mm and even at least 200 mm and even at least 300 mm may be placed, all points of which are farther than 200 mm. of all the edges of the glass, which characterizes a certain size of the glass.
• the glass generally has four edges (also called strips), the distance between two opposite edges being generally greater than 500 mm and more generally greater than 600 mm and more generally greater than 900 mm.
• FIGs 1 to 6 describe a device according to the invention at different stages of the treatment of glass scrolling behind each other.
• the glass here is bulging only by gravity.
• the glass is conveyed from right to left and is bent by gravity.
• This device comprises a train 30 of gravity carriers 31 each carrying a glass 32.
• This train circulates at a lower level 34 of the device, in a tunnel kiln heated to the plastic deformation temperature of the glass.
• the glass collapses under the effect of its weight to finally marry the track of gravity support 31 coming under the periphery of the first main face of the glass.
• Each support carrying a glass arrives in a vertically movable upper form 33 capable of passing from the upper level 35 to the lower level 34 and vice versa.
• This upper form 33 is in a separation chamber 36 whose atmosphere is at a temperature of between 540 and 580 ° C. This upper form 33 comes into contact with the glass only at its periphery of its second main face.
• the contact track of this upper form 33 has a shape complementary to that of gravity carriers 31.
• the upper form 33 can support the glass at the lower level 34 by suction through a skirt 46 surrounding it.
• the specific cooling support 37 laterally movable and shuttle between a position in the upper form 33 in the chamber 36 and a cooling chamber 38 raised to a temperature between 400 and 565 ° C.
• a system of chains 47 makes it possible laterally to move the specific cooling support between the chambers 36 and 38.
• a door 39 is embedded on the structure carrying the specific cooling support and is therefore mobile with it.
• This door thus closes the partition between the chambers 36 and 38 when the specific cooling medium is in the chamber 38.
• this door is against the right-hand partition in the figure of the chamber 36.
• a vertically movable door could have been installed at the level on the wall separating the chambers 36 and 38 and, provided with slides and a system of up and down, perform the function of isolation required between the chambers 36 and 38.
• the glass can be discharged from the specific support 37 by an unloading support 40 carried by an arm 42 of a robot 41. To do this, the unloading support 40 is engaged under the glass still carried by the specific support 37, goes up and supports the glass during its rise, then leaves the chamber 38 by carrying the glass.
• the robot 41 then drives the unloading support 40 carrying the glass to a final device 49 responsible for taking charge of the glass to convey it to a cooling zone for unloading and storing the glass.
• the specific cooling support 37 is of the type of that of FIG. 20 a) referenced 401.
• the unloading support 40 is of the type of that of FIG. 20 b) referenced 400.
• the glass 32 arrives in the form of the upper form 33, the train then marking a stop.
• the robot has already previously discharged a glass 51 on the final device and more particularly on four bars 52 movable vertically.
• a conveyor 53 circulates between the bars 52.
• This conveyor drives support elements 54 (such as suction cups) that can receive the glass when the bars 52 are lowered.
• Figure 2 shows a stage after that of Figure 1.
• the upper form 33 down to the glass 32 to support it.
• the robot 41 engages its unloading support 40 under the specific cooling support 37 and then rises to support the previous glass 29.
• the shape 33 rises with the glass 32, then the specific cooling medium 37 passes empty. from the chamber 38 to the chamber 36.
• the upper form 33 drops, drops the glass 32 on the specific cooling support 37 and goes back ( Figure 3).
• the media train 30 gravitational 31 has advanced one step to the left thus bringing the next glass 45 in the upper form 33.
• the support 37 carrying the glass 32 then passes into chamber 38.
• another glass 45 is supported by the upper form 33 which is lowered to the gravity support train 30 at lower level 34.
• the door 44 rises and the robot 41 engages the unloading support 40 under the specific cooling support 37 ( Figure 4).
• the robot mounts the unloading support 40 so that it supports the glass 32..
• the upper form 33 rises with it the glass 45 in the chamber 36 ( Figure 5).
• the robot then leaves the support 40 carrying the glass 32 of the chamber 38 and the door 44 goes down.
• the specific cooling support 37 has passed from the chamber 38 to the chamber 36 and the shape 33 has dropped to drop the glass 45 onto the support 37 (FIG. 6).
• the robot then places the glass 32 on the device 49, which then drives it to the final cooling zone.
• the glass 45 then follows the same treatment as that followed by the glass 32.
• the temperature homogenization of the peripheral zone of the first main face of the glass begins as soon as the glass is separated from the bending support 31.
• the peripheral zone of the first main face of the glass is then free of contact while the glass is held by the upper form 33 and then supported by the specific cooling medium 37 and the unloading support 40.
• Figures 7 to 13 describe a method and a device according to the invention at different stages of the treatment of glasses moving one behind the other.
• the glass undergoes a step of suction bending between the bending by gravity on a gravity support and laying on the specific cooling medium. The process followed by the glass in the context of this variant is described below.
• the device comprises a train 130 gravity carriers 131 each carrying a glass.
• This train circulates at a lower level 134 of the device, in a tunnel kiln heated to the plastic deformation temperature of the glass.
• the glass sag under the effect of its weight to finally marry the contact track of the gravity support 131 coming under the periphery of the first main face of the glass.
• Each support finally arrives in a vertically movable upper form 233 capable of passing from the upper level 135 to the lower level 134 and vice versa.
• This upper form 233 is in a chamber 236 whose atmosphere is at a temperature between 550 and 590 ° C.
• the contact track of this upper form 233 has a shape complementary to that of the suction mold 200.
• the upper form 233 can support the glass at the lower level. 134 by suction through its skirt 240 surrounding it.
• a lower suction mold 200 whose contact face 201 with the glass is solid and has orifices for communicating a vacuum to the first main face of the glass in the lower position.
• This mold 200 moves between a position in the upper form 233 in the chamber 236 and a chamber 136 juxtaposed heated to a temperature between 500 and 560 ° C.
• This chamber 136 contains an upper form 133 vertically movable and capable of supporting the glass through a skirt 241.
• a specific cooling support 137 laterally movable and shuttle between a position in the upper form 133 in the chamber 136 and a position in the cooling chamber 138 whose temperature is between 350 and 520 ° vs.
• a door 139 is embedded on the structure carrying the specific cooling support 137 and is therefore mobile with it. This door thus closes the partition between the chambers 136 and 138 when the specific cooling medium is in the chamber 138. It closes the partition between the chambers 136 and 236 when the specific cooling support 137 is in the chamber 136.
• a door 239 is embarked on the structure carrying the lower suction mold 200 and is therefore mobile with it.
• This door 239 therefore closes the partition between the chambers 136 and 236 when the lower suction mold 200 is in the chamber 136.
• the support 137 and the mold 200 make a simultaneous translational movement as if they were integral with each other and without modification of the distance that separates them.
• the glass is discharged from the specific cooling support 137 by the unloading support 140 held by the arm 142 of a robot 141.
• the specific cooling support 137 is of the type of FIG. 20 a) referenced 401.
• the support of unloading 140 is of the type of that of Figure 20 b) referenced 400.
• the glass 132 arrives in the upper form 233, the train 130 then marking a stop.
• the upper form 233 goes down to the glass 132 to support it (Figure 8).
• This shape rises with the glass, then the lower suction mold 200 passes empty (without glass) from the chamber 136 to the chamber 236, just as the specific cooling support 137 passes from chamber 138 to chamber 136 ( Figure 9).
• the upper form 233 is lowered with the glass, then slightly presses its periphery to seal the periphery of the glass between the glass and the mold 200 on the one hand and between the different sheets of the stack.
• the suction of the skirt of the form 233 is stopped simultaneously with this pressing.
• the suction of the lower suction mold is triggered while this light pressing has already started.
• the glass is then curved on the lower suction mold and all the sheets of the stack are simultaneously bending due to the pressing exerted periphery, the vacuum being communicated from one sheet to another.
• the form 233 goes back up leaving the glass on the mold 200.
• the mold 200 carrying the glass 132 passes into the chamber 136 in the upper form 133.
• the suction exerted by the mold 200 is stopped when the bending is completed, which generally takes place in the chamber 236 just before the upper form 233 does not rise. Meanwhile, the gravity support train 130 has advanced one step to the left thereby bringing the lens 145 into the upper form 233.
• the upper form 133 is lowered (FIG. 10) to take charge of the lens 132 and back up with him.
• the upper form 233 is also lowered to accommodate the following glass 145.
• the support 137 goes empty from the chamber 138 to the chamber 136 and simultaneously, the mold 200 passes from the chamber 136 to the chamber 236.
• the upper form 133 drops the glass 132 on the specific cooling support 137 and the upper form 233 is lowered to press the glass 145 against the mold 200 (FIG. 11), as already described for the glass 132 (no longer described below). the treatment of glass 145 which is identical to that of glass 132).
• the support 137 carrying the glass 132 passes into the chamber 138.
• the door 144 rises and the robot 141 engages the unloading support 140 under the specific cooling support 137 (FIG. 12).
• the robot then raises the unloading support 140 so that it takes charge of the glass 132.
• the robot then leaves the unloading support 140 carrying the glass 132 of the chamber 138 and the door 144 goes down.
• the robot then places the glass 132 on a final device 49 identical to that already described for FIGS. 1 to 6, for the further cooling (FIG. 13).
• FIG. 14 represents a device identical to that of FIGS. 7 to 13 except that the lower suction mold is replaced by a preliminary specific support 603.
• the displacement of the various elements of this device is identical to that of FIGS. 7 to 13, of the gravity support. 601 to the final device 49.
• the glass reaches its final shape on its gravity support 601 under the separation chamber 600.
• Another difference with respect to the system of FIGS. 7 to 13, the glass is not slightly pressed at the periphery between the shape 602 and the preliminary specific support 603. The glass is simply dropped by the shape 602 on the support 603.
• FIG. 15 represents the evolution of the stresses at the edge of a sheet of glass 1 when one moves away from the edge 2 while going towards the center of the sheet, for a sheet in a) classically obtained according to the prior art and in b) obtained according to the present invention.
• the distance from the edge is represented by the abscissa axis and the stresses in the glass by the ordinate axis.
• the stresses below the x-axis are in compression.
• Those above the x-axis are in extension.
• the stresses in extension usually exceed 5 MPa, which is high.
• the maximum stress in extension can be 3 MPa only what is very favorable to the mechanical strength of the sheet, compared to the case a).
• Figure 16 shows the underside of a curved glass sheet.
• the dotted line 25 is 50 mm from the edge of the sheet and indicates the end of the peripheral zone.
• Line 28 indicates the outer limit of the contact strip for the contact areas of the specific supports. This outer limit may merge with the line 25 or preferably come to at least 60 mm and even 70 mm from the edge.
• Line 26 indicates the inner limit of the contact strip for the contact areas of the specific supports.
• the hatched area 27 between the edge of the glass and the line 25 is the peripheral zone.
• the plane P is a virtual plane perpendicular to the edge of the glass and the sheet. The intersection of the plane P with the lower face defines a segment S. According to the invention, the temperature is homogenized over the 50 mm of this segment from the edge of the sheet.
• the specific supports in contact with the glass in the critical temperature range preferably touch the glass in the zone 161, and without coming into contact with the glass outside the zone 161.
• FIG. 17 represents the respective position of a frame-shaped upper shape 160, a glass 162 and a specific support 163 of the type coming into contact with the glass in the central zone (within the internal boundary of FIG. the peripheral area).
• This situation may arise while the upper form supports the glass initially on the specific support or while the upper form drops the glass on the specific support.
• the management of the glass was carried out following the operation of the suction between the skirt 164 and the upper form 160.
• the upper shape 160 comes into contact with the second main face of the glass so that its outer edge 164 arrives at a distance d1 from the edge of the glass in the range of 3 to 20 mm.
• the distance d2 corresponds to the peripheral zone.
• the distance d3 is the distance between the outer edge of the contact area of the specific support 163 and the edge of the glass.
• the distance between the outer edge of the upper shape and the outer edge of the contact area of the specific support is d3-d1 which is greater than 30 mm.
• FIG. 18 represents a specific cooling support 10 capable of receiving the glass (in this case a stack of two sheets of glass 11 and 12 on one another) without contact with the peripheral zone of its first main face 19 turned towards the bottom.
• This support offers the glass the shape complementary to that which it received to the bending.
• This support comprises a multiplicity of aligned slots 13.
• the upper face 14 of each slot is intended to receive the first main face 19 of the glass in the "contact strip" in the central zone of the glass.
• Each slot 13 is covered with a fibrous material 15 made of refractory fibers well known to those skilled in the art to soften the touch of a tool with the hot glass.
• This support 10 is a frame with one side has a passage 18 to allow the arm to pass an unloading support passing the glass from below.
• FIG. 19 represents a specific cooling support 301 of the peripheral track type carrying a stack of two sheets of glass.
• the glass 300 rests cantilevered by the lower edge 132 of its edge on the peripheral track.
• the glass has no contact with the support in the peripheral zone of its first main face 133, allowing the homogenization according to the invention to occur and to be preserved.
• FIG. 20 shows how an unloading support can support a glass while it is carried by a specific cooling support 401.
• This glass for a windshield includes four bands.
• the specific vacuum cooling medium 401 with its supporting elements 41 1 is seen from the side.
• Its chassis 410 provides a free space 413 allowing the unloading support 400 to enter the chassis 410 under the glass (not shown in a)).
• FIGS. 20b to 20d sequentially show the passage of a glass 407 from a specific cooling support 401 to an unloading support 400.
• the unloading support 400 empty is manipulated by a robot (not shown ) actuating the arm 406. It approaches the specific cooling support 401 carrying a glass 407.
• the unloading support comprises a frame 402 carrying a plurality of support elements 403. These support elements 403 are connected by a end 404 to the frame 402 and have at their other end 405 a contact area to come into contact with the glass. In plan view, the support members 403 are directed outwardly of the frame 402 as one goes from the end 404 to the end 405.
• the specific cooling support 401 carries a glass 407 by a plurality of 408.
• This specific cooling support 401 comprises a frame 410 and a plurality of support elements 408. These support elements 408 are connected by one end 409 to the frame 410 and have at their other end 41 1 a zone contact to come into contact with the glass.
• the support elements 408 are directed towards the inside of the frame 410 when starting from the end 409 to the end 41 1.
• the chassis 401 includes a passage 412 to allow the support 400 to mount (see phase c)) without blocking it.
• the unloading support 400 is placed under the glass without touching it.
• the unloading support 400 actuated by the robot, is mounted and has supported the glass 407, the specific cooling support 401 being discharged.
• This is made possible thanks to the passage 412 in the frame 401 allowing the arm 406 of the unloading support 400 to pass, and thanks to the fact that the support elements 403 and 408 are offset above, the support elements 403 going towards the outside while the support elements 408 go inward.
• the support elements 403 on the one hand and the support elements 408 cross in the manner of the branches of two combs.
• the contact areas of the two supports 400 and 401 can both come into contact with the glass in the same "contact strip" (between 50, even 60 or 70 mm from the edge of the glass and 200 or even 170 mm 150 mm from the edge of the glass) as previously defined, without contacting the glass out of this band.
• the support elements 403 and 408 preferably have their contact area adapted to the shape of the glass they receive, that is to say that their contact zone is oriented towards the glass and is therefore substantially parallel to the zone received glass.
• These support elements may further include a spring to dampen the reception of the glass at the time of its handling.
• the contact areas of the unloading support and the specific cooling medium are at least partially interposed in the contact strip.
• FIG. 21 shows how a specific unloading support 750 can come to support a glass (not shown) initially supported by a specific cooling medium 751 of the track type.
• This track forms, seen from above, an interrupted frame since it includes a passage 752 allowing an arm 753 connected to the unloading support 750 to pass through it by a vertical movement.
• the support 750 comes from below, mounts, supports the glass initially supported by the support 751 and can take the glass to the next step.
• Support 750 carries glass through support members 754.
• Figures 22 and 23 show support elements that can equip a specific cooling medium or unloading support.
• the support member 500 comprises at one of its ends a base 501 provided with orifices for attaching to a frame.
• the other end comprises a contact area 502 to be dressed with a fibrous material 508 to contact the glass.
• the perforated fibrous material 508 is held on the surface of the element by pins 503.
• the contact zone 502 is movable in translation in a direction perpendicular to it and its downward movement is accompanied by the compression of a spring 504.
• FIG. 22 b we see the same support element as in FIG.
• Figure 23 shows another support element provided with a contact zone 601 surrounded by lugs 602 for maintaining a perforated refractory material (not shown) on the surface of the contact zone.
• a contact zone 601 surrounded by lugs 602 for maintaining a perforated refractory material (not shown) on the surface of the contact zone.
• This lack of guide gives an additional degree of freedom to the contact zone which can not only move parallel to the axis of the spring 604 (movement according to the arrow 603) but also can rotate so that the perpendicular to the contact zone deviates from the axis of the spring 604 (movement according to the arrows 605 or 606).

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• Joining Of Glass To Other Materials (AREA)

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• 2017
  • 2017-02-27 FR FR1751568A patent/FR3063287B1/fr not_active Expired - Fee Related
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  • 2018-02-22 CN CN201880001227.4A patent/CN108811497B/zh active Active
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